Wood Decks, Wood Deck Maintenance
While there is growing interest in the use of wood composite and plastic materials, for reasons of cost or aesthetics, most decks built in the United States are made predominantly of pressure-treated pine, cedar or redwood. And all wood surfaces need protection.
by Susan Brimo-Cox
can also be one of the most frustrating to maintain. While there is growing interest in the use of wood composite and plastic materials, for reasons of cost or aesthetics, most decks built in the United States are made predominantly of pressure-treated pine, cedar or redwood. And all wood surfaces need protection. Therein lies the problem for deck owners — and the opportunity for professional painters.
“There are four conditions that cause wood to deteriorate,” says Richard Wallace, director of communications for the Southern Pine Council, “moisture, favorable temperature, oxygen and a source of food, such as wood fiber for termites and other wood-eating insects. The amount of exposure to sunlight [also contributes] to problems.”
Sunlight’s ultraviolet radiation breaks down the cellular structure of wood. According to the U.S. Department of Agriculture’s Forest Products Laboratory in Madison, Wisconsin, the weathering of wood occurs as a result of sunlight, water and abrasion by wind-blown particulates, like sand. Weathering is first signaled by a color change in the wood. Wood fibers then become loose and, over time, erosion of the wood surface takes place.
Water, absorbed by wood, washes out natural resins. Freezing and thawing cycles also accelerate wood’s cellular deterioration and promote rotting, splintering and cracking.
Mold, mildew, algae and fungus are common problems because wood and moisture are natural food sources. Particulate materials, such as dirt, pollen and food, also provide nutrients for these organisms.
Inorganic stains (from the iron in nails or the lime in mortar mixes) and extractive bleeding (from tannins, resins and gums in the wood) also spoil the appearance.
Luckily for professional painters, deck cleaning and maintenance is beginning to become a service market. Rick Mendenhall, manager of the contractor program for Wolman Wood Care Products, says homeowners don’t want to have to take care of the cleaning and maintenance themselves all the time. Enter the painting contractor.
Talk to a dozen wood cleaning experts and you’ll get a dozen recommendations on how to best clean a deck surface. What they do seem to agree on is that you should select the cleaning products and techniques you use based on the deck problems you need to solve. They also agree that proper cleaning and restoration of the wood surface is essential before any refinishing products are applied.
A decade ago, deck-cleaning products were few and pretty much limited to household bleach and detergents. Today, the vast selection of commercially produced deck cleaners, brighteners and restorers can boggle the mind. Luckily – and logically — these products typically fall into several categories.
Chlorine bleach-based products commonly use sodium hypochlorite or calcium hypochlorite—the bleach you find in laundry detergents. Robert Hinderliter, president of Delco Cleaning Systems of Fort Worth, observes that “bleach is the most popular chemical used to clean and brighten a deck. About [half] of the professional contract cleaners use this chemical.”
Bleach is mixed with water to make a diluted solution—typically one part bleach to three parts water, up to half and half proportions. Bleach is effective on mildew and its spores, but doesn’t do much to remove dirt.
The use of chlorine bleach-based products is also controversial. Opponents say the chlorine harms the wood by “melting” the lignin that holds wood cells together. Proponents say chlorine bleach is the only truly effective product to use on mildew.
Pat Coughlin, manager of Brand Development at The Flood Co., recommends cleaning the deck first with a detergent product. Then “check for mildew and algae and spot treat with a bleach-based product if needed. This process avoids having to bleach the whole deck.”
Chlorine bleach should never be mixed with ammonia or any ammonia-based products. The gas that results from the chemical reaction is potentially dangerous.
Oxygen bleach-based products are environmentally friendly. They use sodium percarbonate, a powder that forms hydrogen peroxide and sodium carbonate (soda ash) when mixed with water. The hydrogen peroxide removes mildew and bleaches the gray color. The sodium carbonate removes dirt.
Oxalic acid-based cleaners remove tannin and rust stains. They are not very effective on mildew, so an oxygen- or chlorine-based bleach product is often used first. Oxalic acid cleaners can also neutralize residue left by chlorine bleach-based products. But remember that oxalic acid is a poison and use it with care.
Phosphoric acid removes the gray of aged tannins on unfinished decks. It, too, is environmentally sound.
Citric acid—milder than oxalic acid—is good for decks made of hardwood. Two to eight ounces of citric acid are mixed with a gallon of water.
Trisodium phosphate is another common chemical that can be purchased at the hardware store and mixed with water—one cup of TSP to one gallon of water—to clean a deck.
All this mixing of chemicals leads to the obvious question: Should you mix your own or buy premixed products? It depends on how comfortable you are with chemicals. And if you mix them yourself, there are safety, storage and disposal concerns. On the other hand, premixed products take the guesswork out of the “recipes” and they are relatively inexpensive.
On decks with a painted or stained finish, you need to remove the old finish. If you use a paint stripper, be sure to thoroughly rinse all residue. Sanding is another option. Recommendations for the best results include using an orbital sander, starting with a 40 to 80 grit sand paper and finishing with a 100 grit paper.
Of the mechanical methods, pressure- or power-washing is most favored by contractors. There are numerous advantages, but the rules for pressure-washing vary. Recommendations for the amount of pressure to use can run from 300 up to 3,000 PSI (pounds per square inch). But too much pressure can cause fuzz on the wood surface, especially on softer woods.
The tip you use also plays a role. The experts at Cuprinol recommend a 40-degree tip for light cleaning and rinsing, a 25-degree tip for the average “dirty” deck, and a 15-degree tip for stubborn stains only.
But change is afoot. Hinderliter reports, “There’s been a general trend in the industry over the past 24 months to use stronger chemicals for cleaning and lower pressure.”
After cleaning, decks need to dry 24 to 48 hours before refinishing.
Refinishing and coating products formulated specifically for decks cover the spectrum, from clear to opaque. Some are oil-based. Others are water-based. Some are actually wood preservatives. Some are sealers. Some add natural oils back into the wood and let it “breathe.” Choices are virtually infinite. Discussion with the homeowner will provide clues as to which product to select. But when it comes to color, often there are regional preferences.
“West of the Mississippi, people prefer natural wood tones. They want their wood to look like wood,” reports Heather Stone, marketing director at Performance Coatings Inc. A whitewashed look is more prevalent on the East Coast, she adds.
Adam Churchill, assistant manager for Technical Services & Support at Samuel Cabot Inc., echoes those observations. “Out West, you see people use tones and colors that match wood colors. Grays and Cape Cod gray are the most popular colors overall.”
Steve McGarr, vice president of Sales & Marketing at Duckback Products Inc. says, “We see the popularity of natural tones being used for cedar, redwood and pressure-treated decks.”
Clear finishes offer the least amount of UV protection. John Stauffer, director of the Paint Quality Institute, says, “A lot of people like the wood look and use clear deck coatings—they are quite popular—but they need to be reapplied every year or year-and-a-half. A good rule of thumb is to reapply clear coatings every year whether it looks like it needs it or not.”
Lightly pigmented coatings—toned or semi-transparent—last a little longer. Jake Clark, president and owner of Armstrong-Clark Co., says these products have some UV protection, but let you “see and appreciate the beauty of the wood grain without covering it up.”
Opaque coatings, while they offer the best UV protection, can have problems with cracking and peeling and show traffic wear faster. And, as mentioned earlier, these types of coatings are difficult to remove when it’s time to refinish the deck.
Rick Watson, regional technical manager for Duron Paints & Wallcoverings, likens UV protection of deck coatings to the SPF levels in suntan lotions. Clear stains have an SPF level of 2. Semi-transparent stains have an SPF level equal to 8. Solid-hide stains have an SPF level equal to 20.
Watson reports oil- and acrylic-based stains have their pros and cons, too. “Acrylics and latexes, by nature, have more resistance to UV rays and will hold color longer than oils. Oils will penetrate and actually add moisture back into the dry, weathered, damaged wood.” In the past, oils have been more impact- and abrasion-resistant. Today, technology has improved acrylics substantially. Oil-based coatings also tend to fade and chalk more than acrylic-based products, he says.
he penetrating and moisturizing qualities of oils is what makes them especially appealing to others, however. “When your hands are chapped, you apply a moisturizer. Wood deteriorates because it loses its non-drying oils,” says Clark. To address this problem, Clark’s company has taken a unique approach of combining different types of oils to tackle different problems. He explains, “Our formula is a dry over a non-dry formula—a combination of drying and non-drying oils. The non-drying oils separate and soak down into the wood. The drying oils dry on top and lock in the non-drying oils. The goal of regular deck maintenance is to extend the life of the wood…to keep from replacing it. If you can make it attractive at the same time, it’s a bonus.”
New decks have different requirements than older decks. Stauffer says it’s important that any painting or staining occur early for new decks, with the exception of treated wood with more than 15 percent moisture content. These decks should be allowed to dry for several weeks. “This is especially important with solvent or oil-based finishes which can lock in moisture.”
New decks may also have a hard surface called “mill glaze,” which occurs when the lumber is milled. Sanding removes some of the effects of mill glaze. Exposing the wood to weather for a short time may also help to condition the surface. The Flood Co. says its PenePrep cleaning product is able to etch mill glaze, opening the wood pores to accept coating products.
Performance Coatings has a new product that addresses the special needs of exotic woods. Penofin’s Brazilian Rosewood Oil formula was developed to penetrate into dense woods—such as Ipe, Pau Lope, Ironwood, teak and mahogany. And the oil is a sustainable harvested product pressed from the nuts of the rosewood tree.
As McGarr says, “The key with any paint job is preparation, preparation, preparation. It’s an old adage, but it’s true.” But there are also tips that help ensure the finish is top notch.
An old stand-by—the splash test—will tell you when you should apply or reapply a finish, regardless of the age of the deck.
Wolman’s experts recommend a sample brush-out on your particular wood surface to test for absorption rate and color. And “for even color appearance, the practice of ‘boxing’ together multiple gallons (i.e. pouring several one-gallon cans into a single larger container for mixing) safeguards against brush-out variation.”
The brush is the best applicator, according to Churchill. “Natural bristle for oil-based products; synthetic bristle for water-based products.”
Chris Detter, founder and co-owner of Sunbrite Services Corp. in the Atlanta-area, says, “We use a high volume, low pressure [pump] sprayer. We cut in by hand so there’s no overspray. We massage or back brush with a flat paint pad. It opens the pores and works the sealers in.”
“Professional painters have told us that the kitchen floor sponge mop is a terrific way of putting on a deck coating,” reports Clark. “It pushes the material into the wood, and you can cut a fine line... The only drawback is that splinters and nails or screws will eat it alive.”
Paul Genovese, product manager for Cuprinol Exterior Wood Products, says, “Start at the outside of the deck and work your way in. Spray spindles and handrails first…. When working with horizontal areas, spray four boards at a time working your way down boards. Come back and back brush, pad or broom to guarantee proper uniformity and penetration of the finish.”
Dave Martin, owner of Dave’s Painting in Petaluma, Ca., reports product manufacturers are happy to provide information and educational materials you can use with your customers. “Cabot has a program called ‘dream in color’ [on its Web site] where you can change colors and stains and see what the project will look like before work begins.” He also points out Wolman’s has a contractor certification program that educates contractors about wood care.
Many companies have toll-free numbers for contractors and homeowners to use, and some, like Cabot Stains, provide elaborate wood care guides. By calling Wolman’s technical service department, homeowners can also get hooked up with a contractor in their area.
Clark says, “People need to understand [that deck care] is a maintenance project. Painters should educate the homeowner and encourage them to get on a maintenance schedule.”
Martin says, “We send out newsletters quarterly—each dedicated to an appropriate topic for that season.” His fall newsletter reminds homeowners that with winter coming it’s time to protect their deck for the bad weather ahead. “It’s the power of suggestion,” he explains.
As the experts at Cabot say: “Whether protecting the deck from the scorching heat of the summer sun or guarding it against the damaging wintery effects of ice and snow, a deck finish must be properly selected, applied and maintained to maximize a deck’s beauty and longevity, and most importantly your customer’s investment.” Indeed, you can make their deck an outdoor room they love to live in.